76th Street

The design of Lyndale Avenue bridge over I-494 was unveiled yesterday at Bloomington City Hall. Unfortunately the low turn out (about 12 people) to see the design probably reflects the poor time slot that the viewing was put into (4:00pm-7:00pm). However, the Bloomington city staff that were there were very accommodating to myself and another person that arrived late at kept showing past 7:00pm.

It was nice to see TKDA‘s street scape designs and nicer still to see attempts to correct and improve upon the lack of street scape design from a similar design on the Penn Avenue Bridge. It has the same pressed faux brick concrete on the sidewalk that Penn Avenue has but unlike Penn the median islands have planting, trees and shrubs over the land areas of the islands. However, it looks like most of the islands are going to be combination of concrete and landscape rock (rock mulch), in a design that I would imagine must look pretty from the airplanes would not have any visual impact what so ever from car of pedestrian point of view. The other problem with the concrete rock mulch combination is that it does nothing to help reduce or eliminate the “Heat island” that is created with vast spaces of stone and pavement. Yet another problem with rock is it seems to be inviting trouble by having a collection of rock sitting next an overpass, but maybe I am just a pessimist when it comes to my faith in humanity and lack of belief that no kids will throw rocks over the bridge. So while the light colored concrete and rock proposed is better than asphalt, better still is the use of vegetation.

I can understand TKDA, the designers of the bridge, concerns with site lines and root systems effecting the bridge however, the best solution it seems would be the use of prairie grasses which are drought tolerant and low growing instead of concrete and rock mulch. The biggest problems with prairie grasses, are first to get established they do need to be maintained for the first two years and also problem of perception. Richfield is a city that appreciates its mowed lawns and it may have a difficult time adjusting to unmowed islands. However, Minneapolis made the change of attitude and no longer boats out lawn mowers to mow the islands on Lake of the Isles, Powerhorn, and Loring Park – I think Richfield can make the adjustment too.

The design also showed an increased if not interesting use of railings. Which I while I think it is a good start I think there could be much to improve on. First, they put railing in-front of the islands. It is an interesting but not all necessary. The islands do not need barrier protection from traffic. This is not done with Penn so I imagine it is not needed and it only for effect. But what is the effect? First if the islands are landscaped with plantings, the effect will be to block them from view of cars using Lyndale and somewhat from the pedestrians. The railings have an unfortunate design of concrete for the bottom half and metal railings on the top. Better would be to do what was done near the 76th Street over I-35W Bridge which was metal railings set in concrete posts that go most of the way down exposing the landscaping or to do away with the idea of railings all together. The other problem with the railings is this design creates is a loooong corridor effect. Better would be to break it up with simple unique designs in each island center, using designs not unlike the work by Amy Cordova on Saint Paul’s West Side which consists of organically cut thick plate steel which is allowed to rust naturally. Together with the mosaic on the retaining wall the natural vegetation surround, it makes a stunning yet subdued effect.

The artwork in the island centers would probably cost less than the railing in front of the island centers. That being said, it is important to note that the cost of aesthetic improvements in the design are just a fraction of the over all bridge cost. The decision to upgrade and over build the bridge to a diamond design vs. the lower cost traditional bridge design probably added far more to the overall cost of the bridge than any street scaping improve ever could add.

Hopefully when the city posts the designs on their web site I will have something to show rather than describe.